SAML Logout not sending correct NameID in Logout Request

[rhoerbe]

Rocket.Chat Version: 0.56
Running Instances: 1
DB Replicaset OpLog:
Node Version: 4.5

Sending a LogoutRequest to a Shibboleth IDP results a "Unknown Principal" error response. The reason is that Shibboleth cannot match the NameID from the LogoutRequest with that from the Assertion. I think that meteor is sending a broken NameID in the LogoutRequest:

<samlp:LogoutRequest
    Destination="https://idp5.test.portalverbund.gv.at/idp/profile/SAML2/Redirect/SLO"
    ID="_dbfc10f2b2b46dd43843" IssueInstant="2017-06-08T13:34:12.761Z"
    Version="2.0" xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol">
    <saml:Issuer xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">https://test.ucom.gv.at/_saml/metadata/sp</saml:Issuer>
    <saml:NameID
        Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress"
        NameQualifier="http://id.init8.net:8080/openam"
        SPNameQualifier="https://test.ucom.gv.at/_saml/metadata/sp" xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion">_580bc21719460de9960e40bf07148457</saml:NameID>
    <samlp:SessionIndex xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol">_580bc21719460de9960e40bf07148457</samlp:SessionIndex>
</samlp:LogoutRequest>

When looking at the assertion I find a different NameQualifier and NameID.

    <saml2:Assertion ID="_f59fb807deba37a83b1fec542d87309b"
        IssueInstant="2017-06-08T13:24:14.140Z" Version="2.0" xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion">
        <saml2:Issuer>https://idp5.test.portalverbund.gv.at/idp.xml</saml2:Issuer>
        <saml2:Subject>
            <saml2:NameID
                Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress"
                NameQualifier="https://idp5.test.portalverbund.gv.at/idp.xml"
                SPNameQualifier="https://test.ucom.gv.at/_saml/metadata/sp" xmlns:saml2="urn:oasis:names:tc:SAML:2.0:assertion">test@bmspot.gv.at</saml2:NameID>
            <saml2:SubjectConfirmation Method="urn:oasis:names:tc:SAML:2.0:cm:bearer">
                <saml2:SubjectConfirmationData Address="81.217.70.83"
                    InResponseTo="5DLAKSbj7Eu7vr2Gr"
                    NotOnOrAfter="2017-06-08T13:29:14.272Z" Recipient="https://test.ucom.gv.at/_saml/validate/sp"/>
            </saml2:SubjectConfirmation>
        </saml2:Subject>
...

Expected behaviour: The NameID in the LogoutRequest should match the NameID from the Login.